Small diameter, high torque catheter

• US 5,676,659 A
• Filed: 09/26/1995
• Issued: 10/14/1997
• Est. Priority Date: 11/12/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Ave Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: McGurk, Erin
• Primary Examiner(s): Bockelman, Mark
• Assistant Examiner(s): STRIGHT, RONALD K
• Application Number:
  US08/534,089
• Time in Patent Office: 749 Days
• Field of Search: 604/282, 604/280, 604/281, 604/264, 604/95, 128/658, 138/123-125, 138/137-139, 138/140, 138/141, 138/143-145, 138/153, 427/2.3, 427/2.1
• US Class Current: 604/527
• CPC Class Codes: A61M 2025/0042 Microcatheters, cannula or the like having outside diameters around 1 mm or less
• CPC Class Codes: A61M 2025/0047 the inner layer having a higher lubricity
• CPC Class Codes: A61M 2025/0048 with an outer layer made from silicon
• CPC Class Codes: A61M 25/0012 with embedded structures, e.g. coils, braids, meshes, strands or radiopaque coils
• CPC Class Codes: A61M 25/005 with embedded materials for reinforcement, e.g. wires, coils, braids
• CPC Class Codes: A61M 25/0053 having a variable stiffness along the longitudinal axis, e.g. by varying the pitch of the coil or braid
• CPC Class Codes: A61M 25/0054 with regions for increasing flexibility
• CPC Class Codes: F16L 11/085 comprising one or more braided layers in combination with layers of a helically wound core or wire F16L11/088

Abstract

A catheter comprises an inner tubular member, a braided reinforcement layer, and a soft outer layer. The inner tubular member extends from a proximal end of the catheter to a first distal location. The braided reinforcement layer extends from the proximal end of the catheter to a second distal location which is usually located proximally from the first distal location. The soft outer layer extends from the proximal end of the catheter to a third distal location which is usually located distally of the first distal location. In this way, a catheter having a shaft region, a transition region, and a distal region, each with different strength and flexibility characteristics, can be obtained. Such catheter constructions are particularly useful for very small diameter access catheters.

Claims

1. A catheter consisting of:

an inner tubular member having a proximal end, a distal end, and a lumen extending from the proximal end to the distal end,

a braided reinforcement layer disposed over the inner tubular member and having a proximal end and a distal end, wherein the distal end of the braided reinforcement layer terminates at a distance in the range from 1 cm to 10 cm proximally from the distal end of the inner tubular member; and

a soft outer layer which is a single continuous thermoplastic tube disposed over the braided reinforcement layer and free from seams and junctions, wherein the thermoplastic tube has a proximal portion which is disposed over the braid and the inner tubular member and a distal portion extending distally of the distal end of the inner tubular member by a distance in the range from 1 cm to 10 cm, said distal portion defining a distal lumen extending from and opening into the lumen of the inner tubular member.

2. A catheter as in claim 1, wherein the inner tubular member is composed of a material selected from the group consisting of fluorocarbons, polyamides, polyolefins, and polyimides.

3. A catheter as in claim 2, wherein the inner tubular member is polytetrafluoroethylene.

4. A catheter as in claim 1, wherein the braided reinforcement layer comprises at least one stainless steel braid formed over the inner tubular member.

5. A catheter as in claim 4, wherein the distal end of the stainless steel braid is an annealed and transversely cut distal end and is protrusion less.

6. A catheter as in claim 1, wherein the soft outer layer is composed of a material having a hardness in the range from 30 A to 72 D.

7. A catheter as in claim 6, wherein the material is selected from the group consisting of polyether block copolymer, polyurethane, silicone rubber, nylon, polyethylene, and fluoronated hydrocarbon polymers.

8. A catheter as in claim 1, wherein the catheter is at least 60 cm long, and wherein the braid characteristics of the braided reinforcement layer are selected to increase flexibility within a distal 1 to 60 cm of the catheter relative to a proximal portion of the catheter.

9. A catheter as in claim 1, wherein the soft outer layer is impregnated into the braided reinforcement layer.

10. A catheter body consisting of:

an inner tubular member having a proximal end, a distal end, a lumen extending from the proximal end to the distal end, and having an inner diameter in the range from 0.1 mm to 3.6 mm;

a braided reinforcement layer disposed over the inner tubular member and having a proximal end and a distal end, wherein the distal end of the braided reinforcement layer terminates at a distance in the range from 1 cm to 10 cm proximally from the distal end of the inner tubular member; and

a soft outer layer which is a single continuous thermoplastic tube free from seams and junctions disposed over the braided reinforcement layer and wherein the thermoplastic tube has a proximal portion which is disposed over the braid and the inner tubular member and which extends distally of the distal end of the inner tubular member by a distance in the range from 1 cm to 10 cm, wherein soft outer layer has a distal lumen contiguous with the lumen of the inner tubular member and wherein the outer diameter of the soft outer layer is in the range from 0.33 mm to 4 mm.

11. A catheter body as in claim 10, wherein the inner tubular member is composed of a material selected from the group consisting of fluorocarbons, polyamides, polyolefins, and polyimides.

12. A catheter body as in claim 11, wherein the inner tubular member is polytetrafluoroethylene.

13. A catheter body as in claim 10, wherein the braided reinforcement layer comprises at least one stainless steel braid formed over the inner tubular member.

14. A catheter body as in claim 13, wherein the distal end of the stainless steel braid is an annealed, transversely cut distal end and is protrusion less.

15. A catheter body as in claim 10, wherein the soft outer layer is composed of a material having a hardness in the range from 30 A to 72 D.

16. A catheter body as in claim 15, wherein the material is select from the group consisting of polyether block copolymer, polyurethane, silicone rubber, nylon, polyethylene, and fluoronated hydrocarbon polymers.

17. A catheter body as in claim 10, having a length in the range from about 40 cm to 200 cm.

18. A catheter body as in claim 10, wherein the soft outer layer is impregnated into the braided reinforcement layer.

19. A method for fabricating a catheter, said method consisting of:

providing an inner tubular member having a proximal end, a distal end, and a lumen extending from the proximal end of the distal end;

forming a braid over the inner tubular member from the proximal end to a location spaced proximally from the distal end by a distance in the range from 1 cm to 10 cm; and

forming a soft outer layer by melting a single continuous thermoplastic tube over the braid and the inner tubular member wherein the thermoplastic tube has a proximal portion which is disposed over the braid and inner tubular member and a distal portion of the tube which extends distally beyond the distal end of the inner tubular member by a distance in the range from 1 cm to 10 cm, said distal portion defining a distal lumen opening into the lumen of the inner tubular member and said soft outer layer being free from seams and junctions.

20. A method as in claim 19, wherein the inner tubular member is disposed over a mandrel which extends beyond the distal end of the inner tubular member.

21. A method as in claim 20, further comprising annealing a distal end of the braid and transversely cutting said distal end to remove protrusions.

22. A method as in claim 19, wherein the inner tubular member is composed of a material selected from the group consisting of fluorocarbons, polyamides, polyolefins, and polyimides.

23. A method as in claim 22, wherein the inner tubular member is polytetrafluoroethylene.

24. A method as in claim 19, wherein the soft outer layer is composed of a material having a hardness in the range from 30 A to 72 D.

25. A method as in claim 24, wherein the material is selected from the group consisting of polyether block copolymer, polyurethane, silicone rubber, nylon, polyethylene, and fluoronated hydrocarbon polymers.

26. A method as in claim 19, where a one-over-one stainless steel braid is formed over the inner tubular member.

27. A method as in claim 19, wherein the soft layer is formed by:

placing a mandrel within the inner tubular member;

placing the thermoplastic tube over the braid and the inner tubular member with the mandrel therein; and

applying heat and pressure to melt the thermoplastic and impregnate the thermoplastic into the braid.